[22] For convenience, I set out again the one sentence in the 55-page patent on which Mylan relies in order to show that anastrozole not only inhibits aromatase, but also produces fewer side effects than AG.

It is a particular object of the present invention to provide aromatase inhibitory compounds with fewer undesirable side effects than [AG].

[23] It will be recalled that the question is whether the words “object of the present invention” mean that anastrozole produces fewer effects than AG, as Mylan argues, or whether, as AstraZeneca says, it means that this is what the invention aims to do, without promising that it has succeeded.

(i) undue reliance on dictionary definition

[24] The Judge stated (at para. 132) that the plain meaning of the word “object” suggests that it means an aim to be fulfilled, and referred to the following part of the definition of “object” given in the The Oxford English Dictionary. 3rd ed., on line version:

A goal, purpose, or aim; the end to which effort is directed; the thing sought, aimed at, or striven for.

[25] Mylan makes two points. First, the Judge put undue weight on the dictionary definition of “object”, rather than considering its meaning in the context of patent law. Counsel referred us to cases, including Amfac Foods Inc. v. Irving Pulp & Paper, Ltd. (1986), 12 C.P.R. (3d) 193 (F.C.A.) at 199, where the Court relied on an “object clause” to define the scope of the invention. On the basis of these authorities, he argued that the “object of an invention” was virtually a legal term of art and formed part of the definition of the invention.

[26] I do not agree. Patents are not required to contain a clause describing the object of the invention. When they do, the meaning of the object clause depends on the specific context, including the wording of the particular clause in question and its relationship to the rest of the patent. Indeed, in oral argument counsel conceded that object clauses should not necessarily always be construed as promises of the invention.

[27] Second, counsel for Mylan said that the Judge referred to only some of the dictionary synonyms for, or definitions of, “object”; in particular, he omitted “purpose”, a word that connotes what the invention does. In my view, however, this kind of close semantic parsing of the Judge’s reasons in this case is not productive. Reading them in their entirety, I am satisfied that the Judge placed relatively little weight on the dictionary definitions in reaching his conclusion that the patent does not promise that anastrozole has fewer side effects than AG. For example, he said (at para. 139):

In sum, the plain language of the patent, when read in the context of the patent as a

whole, does not support a promise of fewer undesirable side effects. I accept AstraZeneca’s argument that not all statements of advantage in a patent rise to the level of a promise. A goal is not necessarily a promise. The third paragraph of the 420 Patent refers to a forward looking goal, a hoped-for advantage of the invention.

[28] A better reading of the reasons, in my view, is that the Judge relied on the dictionary definitions and synonyms to confirm that, in its ordinary usage, the word “object” is capable of bearing the meaning that he had assigned to it on the basis of other considerations: the evidence of Dr Dowsett discussed at paragraphs 40-42 of these reasons, and his examination of the patent as a whole.

(ii) context of the patent

[29] In examining the patent in its entirety, the Judge noted that, apart from the “object of the invention” sentence in the specification, nowhere else in the patent is there any indication that anastrozole has fewer side effects than AG. In contrast to the statement of the invention’s object, the claims to the compound anastrozole and its inhibitory effects on aromatase are precise and specific. For example, Claim 13 covers “the compound [anastrozole]”, and Claim 15 relates to “The use of the compound [anastrozole] as an inhibitor of the enzyme aromatase.”

[30] Moreover, it is agreed that the 420 patent would be valid if it only claimed the compound anastrozole and its inhibitory effects on aromatase. It was thus unnecessary for the patent also to promise fewer side effects than AG. Even though tests, which AstraZeneca did not disclose, had been conducted showing that anastrozole was selective, a promise in the patent to this effect would be entirely gratuitous, and could only provide competitors with another basis for attacking its validity.

[31] Mylan counters these arguments by saying that the word “provide”, which appears in the object clause, is used elsewhere in the patent in connection with the claims of the patent. Thus,by stating that “it is a particular object of the invention to provide aromatase inhibitory compounds with fewer undesirable side effects than [AG]”, the object clause should, counsel argues, be interpreted as a promise.

[32] I do not agree. In my view, this microscopic approach to the construction of the provisions of a patent is misguided. The fact that such an ordinary word as “provide” is used in sentences containing the claims of the patent does not mean that when used in other sentences, it should be construed as connoting a promise of the patent.

[33] I agree with the Judge that an examination of the patent as a whole supports the conclusion that, unlike the express claims of the patent, the object clause contains no more than a forward-looking aim of the invention. In my view, the fact that side effects are not mentioned elsewhere in the patent is telling.